Beater element for pulverizing apparatus



7 z 7 a/ E W. ARIQOUR INVENTOR I73 8 O E/l3 4 o JqMEs ATTORNE N 19, 1935 J. w. ARMOUR BEA'IER ELEMENT FOR PULVERIZING APPARATUS Original Filed Febfl9, 1951 Patented Nov. 19, 1935 UNITED STATES PATENT OFFICE BEATER ELEMENT FOR PULVERIZING.

APPARATUS James W. Armour, Worcester, Mass., assignor to Riley Stoker Corporation, Worcester, Mass, a corporation of Massachusetts 2 Claims.

This invention relates to beater elements for pulverizing apparatus, and in is an improvement over the construction disclosed in the patent to Craig, No. 1,714,080, dated May 21, 1929.

This application is a division of my prior application Serial No. 516,893, filed February 19, 1931 and which has matured into Patent 1,941,923, January 2, 1934.

The apparatus shown in said prior patent to Craig comprises a rapidly rotatable disk mouted within, a casing between an inlet opening and an outlet, and serving to divide the space within the easing into two pulverizing zones connected by an annular passage around the edge of the disk. The outlet from the pulverizing chamber leads to a fan chamber having a peripheral discharge. Small segmental wear plates are mounted on both sides of the rotor disk adjacent to its periphery, in order to protect the disk from contact with the material being pulverized. A few of the wear plates on the inlet side of the rotor are provided with integral pr ojections forming agitator pegs, which assist the fiow of air through the machine and prevent excessive accumulation of material in the bottom of the casing. The plates on the outlet side of the rotor are formed with integral projections which serve as grinding pegs and perform most of the actual pulverizing of the material.

The agitator pegs disclosed in the said prior patent to- Craig are massive projections integral with a comparatively thin supporting wear plate. These parts are ordinarily made of white cast iron, unannealed, and the extreme variation in thickness in a single casting has caused internal strains in the metal which have sometimes resulted in cracking of the plate between the bolt holes. Such a crack is extremely dangerous in a rotating part of a high speed pulverizing apparatus.

It is accordingly one object of the invention to provide a massive metallic beater element and a comparatively thin wear plate integral therewith which will be free from the possibility of cracking caused by internal strains in the metal.

With this and other objects in view, as will be apparent to those skilled in the art, my invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawing illustrating one embodiment of my invention and in which like reference numerals indicate like parts,

Fig. 1 is an elevation of a portion of a pulverizer rotor, viewed from the inlet side;

comprises a flat circular rotor disk In which is identical with the disk disclosed in the patent to Craig No. 1,714,080 and is intended to be rotatably mounted in a pulverizing apparatus of the same general type as that shown in said patent.

In order to protect this disk from the abrasive action of the material being pulverized, I provide a plurality oi fiat comparatively thin Wear plates ll, made in segments and each shaped as a circular ring sector. These plates are mounted closely adjacent to each other on the peripheral portion of the rotor disk and on the side thereof toward the inlet (not shown). The outer edge of each plate is provided with a laterally projecting flange I2 which overlies the periphery of the rotor disk and prevents any contact thereby with the material undergoing pulverization.

Each of the plates II is provided on its rear side, which comes next tothe disk, with a cylindrical projection H! which fits in a similarly shaped opening in the rotor disk and serves to locate the plate properly and hold it against centrifugal force. This projection 14 is preferably cast inside of a flanged ferrule I5, as described in said prior patent to Craig, to insure a smooth and accurate fit. The plates are held against the disk by means of plow bolts l0, which are preferably arranged in two circular rows. Each bolt in the inner row is located on the radial center line of one of the plates 1 I, and each bolt in the outer row is located on the joint between adjacent plates. In order to accommodate these bolts, each plate has a bolt hole I! on its radial center line and a half bolt hole IS on each side edge near the outer peripheral edge of the plate.

These bolt holes I1 and I8 are countersunk at I9 The at 22 to insure proper setting of the bolt heads.

Raised portions or bosses 23 are provided at the inner ends of the bolt holes to contact with the disk and form a three-point support. These bosses prevent any bending stresses from reaching the plates as the bolts are tightened.

Certain of the plates H are provided on the exposed face with a laterally extending projection 25 which serves as an agitator peg and by sweeping through the lower portion of the casing prevents any accumulation of coarse material at this point. There are preferably only a small number of these pegs 25, so that tramp iron may be readily disposed of in the manner described in said prior patent.

The agitator peg 25 is located directly on the radial center line of the plate H and flush with the outer periphery of the plate. The side faces 25 of the peg are substantially radial and the outer surface of the peg is curved with a comparatively large radius at 21 and slopes gradually inwardly at 28 to the plate close to the bolt hole H. A pair of ribs 38 form continuations of the side faces 25 of the peg and extend at each side of the bolt hole l1. These ribs 38 not only increase the area of the side faces and thus provide an additional fan action to assist the flow of air through the machine, but they also greatly strengthen the plate H between the bolt holes H and i8. There is therefore much less danger of the plate H cracking as a result of internal strains in the metal caused by the great difference in section between the massive peg and the thin plate. A recess 32 may be provided in the back of the plate between the locating projection I4 and the flange I2. This lightens the casting without affecting its wearing qualities and aids in obtaining more uniform cooling during the casting operation. The exposed face of the plate may be beveled at 33 adjacent its inner :edge to avoid a ledge which might be struck by tramp metal.

On the other side of the disk I toward the cutlet (not shown) I provide a second series of Wear plates 35 (Fig. 2) which in certain respects are similar to the plates ll. Each plate 35 is likewise shaped as a circular ring sector, and is held in place by the hexagonal nuts 36 of the plow bolts [6. The plates 35 are provided with two annular rows of pulverizing pegs 31. Since the plates 35 are disclosed and claimed in my prior application, Serial No. 516,893, of which this application is a division, they will not be described in detail herein.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A beater element for a pulverizing apparatus comprising a rotor wear plate shaped as a circular ring sector, said plate having a bolt hole on its radial center line and a half bolt hole at each side edge near its outer periphery, a peg integral with the plate and extending from one face thereof near the outer periphery, said peg having substantially radial side faces and an outer surface which is curved with a comparatively large radius and slopes gradually inwardly to the plate close to the center bolt hole, and a pair of strengthening ribs connected with the eg which form continuations of its radial side faces and extend at each side of the center bolt hole.

2. A beater element for a pulverizing apparatus comprising a rotor wear plate shaped as a circular ring sector, said plate having a bolt hole on its radial center line, a peg integral with the plate and extending from one face thereof near the outer periphery, said peg having substantially radial side faces, and a pair of strengthening ribs connected with the peg which form continnations of its radial side faces and extend at each side of the center bolt hole.

JAMES W. ARMOUR. 

